RCAAP Repository

The Aquaculture Center of Unesp, Jaboticabal, SP, Brazil, received fishes for diagnosis from fish farmers reporting fish crowding at pond edges and in water inlets. Fifty-three out of 194 cases showed round to oval, immobile whitish structures, measuring up to 162 mm diameter, identified as the dinoflagellate Piscinoodinium pillulare. In 34 diagnosed cases the parasites were present in the gills, in 2 on body surface, and 9 in both. Thirty-one out of 53 were tambacu hybrids hosts; 7, Piaractus mesopotamicus; 6, Colossoma macropomum; 5, Leporinus macrocephalus; 3, Oreochromis niloticus; and 1, Prochilodus lineatus. Fish showed increased mucous production on body surface and gills, while ecchymosis in the caudal peduncle and operculum was present. The gills also showed paleness, congestion, and petechiae. Histopathology presented a great number of trophonts situated between secondary lamellae, fixed to or detached from the epithelium. Primary lamellae presented interstitial hemorrhages, severe hyperplasia of the epithelium, goblet cells, and mononuclear infiltrates. The present work is the first report of P. pillulare in Brazil and emphasizes the importance of this dinoflagellate which caused significant economic losses from 1995 through 1997.

African beetles Onthophagus gazella from both sexes were analyzed by electrophoresis for an investigation of esterase isozymes using alpha-naphthyl propionate and methylumbelliferyl propionate as substrates. Only one of the esterases (Est. 6) reacted with one of the substrates (alpha-naphthyl propionate). Six areas of activity were found, two of them being polymorphic (Est. 3 and Est. 4). For presence of Est. 3, 337 individuals were analyzed, including descendants of 32 controlled crossings: two alleles were identified, whose frequencies are Est. 3A = 0.447 and Est. 3B = 0.553. The population is in equilibrium for this locus (qui-square = 4.18; 0.2 > P > 0.1). For Est. 4, 338 individuals, descendants of 32 controlled crossings, were analysed. In this case, three alleles were identified whose frequencies are: Est. 4A = 0.277; Est. 4B = 0.661; and Est. 4C = 0.062. The population is not in equilibrium for this locus (qui-square = 40.259; p < 0.001). Two esterases were detected only in the pupal stage and another one in larvae. Of the 23 loci analyzed in these insects up to now, 3 are polymorphic (13%), which indicates very low variability in the population here studied.

Farmers in the Paranapanema Valley (São Paulo, Brazil) have reported problems with flocks of Eared Doves (Zenaida auriculata) eating sprouting soybeans. In this region these birds breed colonially in sugar-cane, and eat four crop seeds, using 70% of the dry weight, in the following order of importance: maize, wheat, rice, and soybeans. Three weeds (Euphorbia heterophylla, Brachiaria plantaginea, and Commelina benghalensis) were important. This information suggests that the doves adapted particularly well to the landscape created by the agricultural practices in the region, exploiting many available foods.

Larvae of Anicla infecta (Ochsenheimer, 1816) (Noctuidae) feed upon many grasses and may be harmful to cereals and fodder of economic importance. This study was developed aiming to contribute to knowledge of the biology of this species. The rearing was done in an environmental chamber with the following settings: temperature of 25 ± 1ºC; relative humidity of 70% <FONT FACE=Symbol>±</FONT> 10%, and photoperiod of L14: D10. The larvae fed on ryegrass, Lolium multiflorum Lam. The results express the mean and standard error for the length of every stage in days. For each stage we observed the following time of development: egg 3.2 <FONT FACE=Symbol>±</FONT> 0.09; larvae 18.7 <FONT FACE=Symbol>±</FONT> 0.07; pre-pupae 3.3 <FONT FACE=Symbol>±</FONT> 0.04; pupae 12.6 <FONT FACE=Symbol>±</FONT> 0.14; and adult longevity was 12.1 <FONT FACE=Symbol>±</FONT> 1.03. Also the pre-egg-laying period was 4.4 <FONT FACE=Symbol>±</FONT> 0.59; the egg-laying period was 8.1 <FONT FACE=Symbol>±</FONT> 0.84; and the post-egg-laying period was 0.3 <FONT FACE=Symbol>±</FONT> 0.14. The mean number of egg-laying cycles per female was 6.7 <FONT FACE=Symbol>±</FONT> 0.73; that of eggs per cycle was 77.5 <FONT FACE=Symbol>±</FONT> 4.37; and total eggs per female was 521.4 <FONT FACE=Symbol>±</FONT> 47.36.

The breeding structure of both colony and population of social insects can be examined by genetic analysis. Colonies of the leaf-cutting ants Acromyrmex heyeri and A. striatus (Myrmicinae, Attini) were thus analyzed for isoenzyme systems MDH, a-GPDH, and AMY to describe genotype variability and social structure. A total of five loci were investigated (three for amylase and one for each other system). Ninety-seven colonies of A. heyeri and 103 of A. striatus were sampled in different localities in Southern Brazil (State of Rio Grande do Sul). The genotypes found show the occurrence of monogyny and polygyny associated or not with polyandry, which indicates that the social organization is colony-specific. The polygyny and polyandry observed are likely to be responsible for the great genotypic diversity of the colonies. The average inbreeding coefficient per colony was higher in A. striatus than in A. heyeri, which may reflect the different patterns of production of sexual individuals and nuptial flight of those two species.

In order to evaluate melatonin implication in the regulating of its own secretory process by pinealocytes, we used morphometric techniques for transmission electron microscopy. In mice treated with 100 mg of melatonin (N-acetyl-5-methoxy-tryptamine) by daily subcutaneous injection, we observed a decrease in number and volumetric density of lysosomes. Our results showed that melatonin influences the secretory activity of pinealocytes and participates in a complex secretory regulating mechanism.

Androlaelaps marmosops, a new species of laelapid mite, is described from the pelage of the mouse opossum, Marmosops incanus (Lund, 1840) (Mammalia: Didelphidae), in two areas of Atlantic Forest of Rio de Janeiro State. Measurements and illustrations are included for females only.

Although Nasua nasua is broadly distributed geographically and relatively common, it is still little studied. This paper reports observations of coatis in an Atlantic Forest area, the Parque Estadual Carlos Botelho (PECB) in São Paulo State, Brazil. The social structure of coatis at PECB seems to be the same related in the literature. The mating season appears to be August-September and the pups are born in October-November. Coatis are mainly arboreal at the PECB, contrasting with habits reported in the data from other areas. This preference for the arboreal stratum no doubt is related to their foraging in epiphytic bromeliads, which occurred in 90.6% of the instances in which they were observed feeding. Bromeliads are a rich food source much more common in the Atlantic Forest than in other areas where coatis have been observed. This result suggests that this species is able to adjust its foraging and strata preferences to different environments without changing its basic social structure.

The effects of mycorrhizal inoculation and increasing soil P levels on the expression of total proteins and peroxidase activity on passion fruit roots were evaluated. The experimental design was entirely at random, with four treatments of inoculation (a - control; b - Gigaspora albida; c - Scutellospora heterogama; d - mixture of G. albida, G. margarita, S. heterogama, and Glomus clarum) × three levels of soil P (4, 11, and 30 mg/dm³ of soil), each with three replicates. Plants were harvested 70 days after inoculation, when root colonization, shoot P level, protein content, and enzymatic activity of peroxidase (PAGE - 7%) on root extract were evaluated. Regarding protein, there was no significant difference among the treatments, except between those roots receiving mixed inoculum and 11 mg P/dm³ of soil. Effect of P on protein concentration, when compared with the inoculation effect was observed. For peroxidase, there was an eletrophoretic band common to all treatments (rf: 0.43) and another that was absent only in noncolonized plants, grown in soil with lower P (rf: 0.46). Mycorrhizal specific bands were not present but a small decrease of intensity of bands in noncolonized plants was observed. Conversely, the control roots presented a single band (rf: 0.33) not observed in the other extracts, that may demonstrate an inhibitory effect of AMF on some host activities. The data showed the influence of P level in soil on the protein expression of roots, suggesting the influence of this nutrient on root genetic expression as well as on the mechanisms of symbiotic control/recognition.

No summary/description provided

No summary/description provided

Spatial and temporal variation of climatic and physical characteristics in a shallow tropical reservoir in the city of São Paulo, Southeastern Brazil, and their possible influence on the dynamics of the phytoplankton population. Samples were taken at 5 depths of the water column (subsurface: 1% Io, 10% Io, 2 m, and bottom) and at 4 hour intervals (6:00, 10:00, 14:00, 18:00, 22:00, 2:00, and 6:00 h) during summer (March 3-4), fall (June 13-14), winter (August 29-30), and spring (November 29-30) of 1994 at a single sampling station. Garças Reservoir (23º39'S, 46º37'W) is a kinetic turbulent system, highly influenced by winds, with stratification that may last for days or weeks, and which undergoes mixing periods more than once in a year. A thermal pattern of this type is comparable to the warm discontinuous polymictic. Considering its optical properties, the water body was classified as an ecosystem with moderate turbidity, which decreases basically due to increased phaeopigment concentration during the spring. Also, the reservoir is an ecosystem whose phytoplanktonic community is subjected to stress, the degree of which depends on level of light penetration.

A study was conducted in an early second-growth forest aiming at knowing the richness, relative abundance, seasonal distribution, and hourly frequency of euglossine bees, and their association with scent baits. Male bees were attracted to cineole, vanillin, methyl salicylate, and eugenol. The baits were hooked 1.5 m high and 6 m from one another. The specimens were collected from December 1997 to November 1998, once a month, from 7:00 to 17:00 h. A total of 339 male euglossine bees were caughts, accounting for 19 species and four genera. The most common species was E. cordata, making up 69.9% of the individuals, followed by E. truncata (2.3%), E. violaceifrons, and E. smaragdina (2.1%). The most attractive scent was cineole, which baited 87% of the specimens and 73.7% of the species. Vanillin, the second most visited bait, eured 7.6% of the specimens and 26.3% of the species. E. surinamensis was only collected with this bait. Methyl salicylate and eugenol baited combined 2.6% of the specimens. However, by species numbers Methyl salicylate attracted 21% whereas eugenol was attractive for 15.8% of them. In general, the species were more abundantly found in the rainy season (January-June). The hourly activity data showed that the euglossine bees were attracted to the baits all day long, but at a higher frequency in the morning period, peaking between 8:00 and 10:00 h.

The aims of this study were to verify the distribution of births of captive maned wolves Chrysocyon brachyurus and the causes of their deaths during the period from 1980 to 1998, based on the registry of births and deaths in the International Studbook for Maned Wolves. To determine birth distribution and average litter size, 361 parturitions were analyzed for the 1989-98 period. To analyze causes of mortality, the animals were divided into four groups: 1. pups born in captivity that died prior to one year of age; 2. animals born in captivity that died at more than one year of age; 3. animals captured in the wild that died at any age; and 4. all animals that died during the 1980-98 period. In group 1, the main causes of mortality were parental incompetence (67%), infectious diseases, (9%) and digestive system disorders (5%). The average mortality rate for pups was 56%. Parental incompetence was responsible for 95% of pup deaths during the first week of life. In group 2, the main causes were euthanasia (18%) and disorders of the genitourinary (10%) and digestive systems (8%). Euthanasia was implemented due to senility, congenital disorders, degenerative diseases, and trauma. In group 3, the main causes were digestive system disorders (12%), infectious diseases (10%), and lesions or accidents (10%). The main causes of mortality of maned wolves in captivity (group 4) were parental incompetence (38%), infectious diseases (9%), and digestive system disorders (7%).

Seaweed preference by the Brazilian endemic gastropod Astraea latispina was examined in the laboratory to evaluate the role of secondary metabolites in determining food choice. Of three species of seaweeds examined, Plocamium brasiliense was highly preferred; less so were Sargassum furcatum and Dictyota cervicornis were preferred less. Extracts and/or pure major metabolites of the two potentially chemically-defended seaweeds (P. brasiliense and D. cervicornis) were tested as feeding deterrents against A. latispina. Algal extract assays demonstrated that three concentrations of crude organic extract of the red alga P. brasiliense (50%, 100%: natural concentration, and 200% of dry weight: dw) did not affect feeding of this gastropod. In contrast, the three concentrations of crude organic extract of the brown alga D. cervicornis (50%, 100% and 200% dw) inhibited feeding by A. latispina. The chemical deterrent property of D. cervicornis extract against the gastropod A. latispina occurred due to a mixture of the secodolastane diterpenes isolinearol/linearol (4:1 -- 0.08% dry weight). This is the first report showing that Dictyota cervicornis produces a chemical defense against herbivores using secodolastane diterpenoid. In addition, these results widen the action spectrum of secondary metabolites found in seaweed belonging to this brown algal genus.

For evaluating the trophic relationship between early life stages of fish and zooplankton in Lake Monte Alegre, fish distribution and feeding habits have been studied in areas with and without macrophytes. In the first of these areas, 356 specimens belonging to 8 species, mostly juveniles, were caught by a sieve. Another 35 specimens, belonging to 4 species, were caught by gill nets and seine in areas lacking macrophytes. Their diets were composed of aquatic insects, microcrustaceans, rotifers, detritus, and other aquatic invertebrates. Microcrustacean prey were mainly littoral or benthic dwellers, found in the highest proportion in specimens of 7-20 mm SL. Most fish species have parental care, which could explain the absence of planktonic larvae. Early life stages of fish do not exert a predation pressure on the lake zooplankton.

The aim of this paper was to verify hydrological and hydrochemical changes in the Iquiparí Lagoon water column, during three months, as related to an artificial sand bar opening. A drastic reduction in water volume occurred 28 hours after the sand bar opening, exposing the bottom sediment. This was densely colonized by submerged aquatic plants, which were dominant in the ecosystem metabolism, specially near the sand bar. An increase in salinity values, and dissolved and total nutrient concentrations, was observed during the sand bar opening period. In contrast, chlorophyll a concentration decreased. These changes were associated with: 1) mix of remained brackish and marine waters; 2) nutrient release from sediments by physical processes; and 3) submerged plant death. After the sand bar closure, lagoon metabolism was completely regulated by a dense phytoplankton community. We observed that the sand bar opening resulted in an extensile replacement of the lagoon's water and a change in the community mainly responsible for the ecosystem metabolism.

The influence of Eucalyptus plantations on the structure and composition of macroinvertebrate communities associated with the aquatic fern Salvinia auriculata Aublet were investigated in a high altitude lake bordered by either secondary Atlantic forest or Eucalyptus plantations. Comparisons of the diversity of Chironomidae (Diptera, Insecta) larvae in the littoral zone between these two vegetation types showed higher diversity of larvae in waters bordered by Eucalyptus. The results demonstrated that the predominance of carnivorous taxa among the macroinvertebrate fauna appears to be the major controlling factor for limiting diversity in lake areas bordered by Eucalyptus.

Distribution, sources of mortality, and survivorship of immatures was investigated during the reproductive season of the neotropical buprestid leaf miner, Pachyschelus coeruleipennis, that burrows in leaves of Croton floribundus (Euphorbiaceae) in SE, Brazil. Immature distribution was investigated by a random sample of 120 shrubs of C. floribundus growing along forest edges. Marked leaves were followed to recorded sources of mortality and survivorship of immature stages. Females lay their eggs preferentially in the young leaves of the host plant, with mines and pupal cells having been found on the middle part of plants. Densities of eggs, active mines, and pupal cells were, respectively, 25 ± 2, 6 ± 1, and 1 ± 0.3 per 100 leaves. Predators and parasitoids accounted for the majority of losses in the immature P. coeruleipennis population. Mortality was 3 times lower in the egg stage than in the last larval instar. Predation rate was greater than parasitism but the latter increased much more during the development of immatures. Survivorship and sources of mortality were different between early and late season sample of leaf-miner immatures. Parasitism rate was greater in the late-season whereas predation was greater in early-season samples. These results are compared with mortality patterns described for other buprestid leaf miners in temperate and tropical regions.

Diversity and biomass of Chironomidae larvae were studied between January-November 1993 and March-November 1994 in an impacted lagoon in Rio de Janeiro, Southeastern Brazil, in an attempt to establish the ecological consequences of anthropogenic eutrophication processes. Nine hundred and seventy-five organisms belonging to the Tanypodinae, Orthocladiinae, and Chironominae were collected. Polypedilum (62%) and Chironomus (58%) were the most common genera found in the limnetic and littoral zones.